The present invention relates to testing of data packet signal transceivers, and in particular, to systems and methods for parallel testing of multiple such devices.
Many consumer electronics products, particularly, hand-held devices, use various wireless signal technologies, both for connectivity as well as communications purposes. Because such wireless devices transmit and receive electromagnetic waves, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless technologies subscribe to various wireless signal technology standard specifications.
When designing and manufacturing such devices, manufacturers take extraordinary care to ensure that such devices will meet or exceed the prescribed standard-based specifications for each wireless technology used by such devices. Furthermore, once these devices are in mass production, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless technology standard-based specifications.
As part of such manufacturing test, current wireless device test systems employ a subsystem for analyzing signals received from a device, e.g., a vector signal analyzer (VSA), as well as a subsystem for generating signals to be received by the device, e.g., a vector signal generator (VSG). The analyses performed by a VSA and the signals generated by a VSG are usually programmable, so as to allow each subsystem to be used for testing devices in accordance with a variety of wireless technology standards, including those with differing frequency ranges, bandwidths and modulation characteristics.
Wireless device manufacturers are under constant pressure to keep manufacturing and testing costs down in order to preserve profit margins facing constant reduction pressures due to competition and consumer expectations of new and additional features at no more, or even lower, costs than previous models. Accordingly, systems and techniques for performing manufacturing tests of devices using the various wireless technologies are designed to test using less time and less testing hardware. For example, in addition to reducing handling and set-up times, some test systems are designed to test multiple devices under test (DUTs) concurrently (often referred to as “parallel testing”).
As with single-DUT testing, a tester must determine that a device is ready to receive or send test signals. With parallel testing, establishing readiness of a DUT can be far more complicated and time consuming. For example, if a tester sends a set of identical readiness packets to multiple DUTs, it is often the case that one or more of the DUTs may not receive it, i.e., the DUT is not yet ready. Ideally, one would wish to halt sending readiness packets to the DUTs that did acknowledge receipt, while continuing to send readiness packets to those DUTs who have not yet acknowledged receipt, until all DUTs have indicated their readiness. However, halting the sending of packets to some DUTs while continuing to send them to others raises the possibility of packet leakage, i.e., reception of data packets by DUTs not intended to receive such data packets.
Accordingly, it would be desirable to have a test system and method for establishing readiness of multiple DUTs for parallel testing while requiring a minimal time interval for establishing readiness of all DUTs, and not having those DUTs responding as ready more quickly also receiving unintended tests signals.